Smoking prevalence has been steadily declining for much of the past 40 years, but recent data show that smoking is on the rise among young people. College students, in particular, have shown sharp increases in the prevalence of smoking since the early 1990s. Most college students who smoke are light, occasional smokers, but data from available longitudinal studies demonstrate that many students will become ensnared by tobacco dependence during college and will continue to smoke for 10 or more years. To date, research on college smoking has relied on epidemiological methods that have been limited in their ability to characterize in detail college students' smoking patterns and the motivational factors related to smoking in students. This project is designed to extend existing research by using the powerful techniques of Ecological Momentary Assessment (EMA) to collect real-time reports of college smokers' behaviors and subjective states. In this research, 80 college smokers will carry electronic diaries (EDs) programmed with interactive diary forms. The EDs will prompt subjects randomly four times per day for a period of two weeks. Subjects will also complete brief diary entries when cigarettes are smoked. Mood data from college smokers will be contrasted with those obtained from a comparison group of 80 non-smoking college students. Central questions addressed by the proposed research include: (1) What are the typical smoking patterns observed in college smokers? This project will generate descriptive information about smoking patterns that is much richer than that available from existing survey research. (2) Do college smokers and nonsmokers differ in the severity or patterning of negative affect? Negative mood is cited as one of the most potent motivators of smoking in both youth and adults, but no available data address smoking-mood relations in college smokers. (3) Do college smokers derive negative reinforcement from smoking, and if so, how much? Researchers have speculated that many college smokers may begin smoking to cope with college pressures, but no research has assessed how much negative reinforcement college smokers obtain from cigarettes in their natural environments. This project has the potential to address key questions about the early smoking career in a population at risk for the development of chronic tobacco dependence.